Substituted benzoyl (hetero) cyclic diones

ABSTRACT

Substituted aryl or heteroaryl in particular benzoyl bicycloalkanediones and related compounds, intermediates therefor, synthesis thereof, and the use of said diones for the control of weeds.

This is a Continuation of application Ser. No. 07/411,086, filed on Sep.22, 1989, now U.S. Pat. No. 5,623,124 which is a Continuation-In-Part ofapplicaiton Ser. No. 07/182,534, filed on Apr. 18, 1988, now abandoned.

This invention relates to novel substituted aryl or heteroaroyl, inparticular benzoyl, bicycloalkanediones and related compounds,intermediates therefor, synthesis thereof, and the use of said compoundsfor the control of weeds and acari.

More particularly, this invention concerns compounds of the generalformula ##STR1## wherein A is a bicyclic 1-one-2-ene-3-ol-2yl residue;

B is an aryl or heteroaryl group optionally bearing substituents; andsalts, enolethers and enolesters thereof.

A particular group of compounds is that represented by formula I##STR2## wherein,

Ar is selected from the groups ##STR3##

X is oxygen, sulfur or C₁₋₄ alkylene;

each of R¹, R², R³, R⁴, R⁹ and R¹⁰ is, independently, hydrogen, C₁₋₈alkyl or COOR¹⁶ ;

R⁵ is C₁₋₈ alkyl, optionally substituted with one to six halogen atoms;C₁₋₈ alkoxy, optionally substituted with one to six halogen atoms; (C₁₋₈alkyl) carbonyl; (C₁₋₈ alkoxy) carbonyl; NR¹³ R¹⁴ ; O_(n) S(O)_(n),R¹² ;NR¹⁵ SO₂ R¹² ; halogen; cyano; or nitro;

each of R⁶ and R⁷ is independently hydrogen or selected from the valuesof R⁵ ; or R⁶ and R⁷ together form the group -Y-W-Z-;

R⁸ is hydrogen, C₁₋₈ alkyl, optionally substituted (C₁₋₈ alkyl)carbonyl,optionally substituted (C₁₋₈ alkoxy)carbonyl, C(O)NR¹³ R¹⁴, C₁₋₈alkylsulfonyl, P(O)--(OR¹¹)₂, R¹³ P(O)OR¹¹ or optionally substitutedbenzoyl or a salt forming moiety;

R¹¹ is C₁₋₈ alkyl;

R¹² is C₁₋₈ alkyl, optionally substituted with one to six halogen atoms;

each of R¹³, R¹⁴, R¹⁵ and R¹⁶ is, independently, hydrogen or C₁₋₈ alkyl;

each of R¹⁷ and R¹⁸ is independently hydrogen, halogen, or C₁₋₈ alkyloptionally substituted with one to six halogen atoms; or R¹⁷ and R¹⁸together form an oxo group;

each of R¹⁹ and R²⁰ is, independently, hydrogen, halogen, or C₁₋₈ alkyloptionally substituted with one to six halogen atoms;

W is --(CR¹⁷ R¹⁸)_(t) --(CR¹⁹ R²⁰)_(t') -- or SO₂ ;

each of Y and Z is independently oxygen, sulfur, SO₂, C--O or CR¹⁵ R¹⁶ ;with the proviso that Y and Z are attached to adjacent carbons;

n is zero or one;

n' is zero, one or two;

q is zero, one or two;

t is one or two; and

t' is zero or one.

Enol compounds of the formula (I), wherein R⁸ is H, can exist in anumber of tautomeric forms, the following being representative; ##STR4##

It is intended that all such tautomeric structures are included withinthe scope of this invention.

In the description and claims hereinafter, each of W, X, Y, Z, n, n', q,t, t' and R¹ -R²⁰ is as defined above, unless otherwise specified.

In the practice of the present invention, X is preferably oxygen or C₁₋₂alkylene, especially C₁₋₂ alkylene, particularly --CH₂ --.

Ar is preferably substituted phenyl.

Where any of the substituents R⁵ -R⁷, R¹² and R¹⁷ -R²⁰ is or compriseshalogen, such halogen is conveniently selected from bromo, chloro andfluoro.

Where any of R¹ -R²⁰ is or comprises C₁₋₈ alkyl, it is preferably of oneto four carbons.

Where any of R⁵ -R⁸ is or comprises C₁₋₈ alkoxy, it is preferably of oneto four carbons.

Each of R¹ -R⁴, R⁹ and R¹⁰ is preferably hydrogen or C₁₋₄ alkyl; suchalkyl is more preferably of one to three carbons; each of R¹ -R⁴, R⁹ andR¹⁰ is more preferably hydrogen.

R⁵ conveniently signifies hydrogen, C₁₋₄ alkyl optionally substitutedwith halogen, --(O)_(n) --S(O)_(n),--C₁₋₄ alkyl, halogen or nitro. It ispreferably methyl, CF₃, C₁₋₃ alkylsulfonyl, C₁₋₃ alkylsulfonyloxy,chloro, bromo or nitro especially nitro.

R⁶ is preferably hydrogen, C₁₋₄ alkyl, C₁₋₄ alkoxy, bromo, chloro or,together with R⁷, the group -Y-W-Z-; it is more preferably hydrogen,methoxy or chloro, or, together with R⁷, methylenedioxy; more preferablyhydrogen.

R⁷ is preferably bromo, chloro, fluoro, OSO₂ C₁₋₄ alkyl, SO₂ C₁₋₄ alkyl,OSO₂ C₁₋₄ haloalkyl, SC₁₋₄ alkyl, SOC₁₋₄ alkyl, NR¹⁵ SO₂ C₁₋₄ alkyl, or,together with R⁶, the group -Y-W-Z-. It is more preferably chloro,fluoro, bromo, C₁₋₃ alkylthio, C₁₋₃ alkylsulfonyl or C₁₋₃alkylsulfonyloxy, or, together with R6, methylenedioxy.

Examples of various preferred compound groups comprising R⁸ are

(a) R⁸ -hydrogen, C₁₋₈ alkyl, (C₁₋₈ alkyl) carbonyl, (C₁₋₈alkoxy)carbonyl, C(O)NR¹³ R¹⁴, C₁₋₈ alkylsulfonyl P(O)--(OR¹¹)₂, R¹³P(O)OR¹¹ or benzoyl or a salt forming moiety

(b) R⁸ -hydrogen, C₁₋₄ alkyl, C₁₋₄ alkylcarbonyl, benzoyl or C₁₋₄alkylsulfonyl

(c) hydrogen, methyl, ethyl, t-butylcarbonyl, isobutylcarbonyl, benzoylor methylsulfonyl

(d) hydrogen

(e) optionally substituted (C₁₋₈ alkyl)carbonyl, optionally substituted(C₁₋₈ alkoxy)carbonyl, optionally substituted benzoyl

(f) (C₁₋₈ alkoxy)carbonyl.

Where R⁸ is a salt forming moiety, it may be inorganic e.g. a metalequivalent of Na, Ca, Fe or Cu; or organic, e.g., the ammonium saltmoiety of an amine e.g. 1-(methylaminomethyl)naphthalene), a sulfonium,sulfoxomium or phosphonium moiety. Preferred examples of ammonium saltsare those derived from amines having the Formula X. ##STR5## whereineach of R²¹, R²² and R²³ represents independently hydrogen, C₁₋₁₆ alkyloptionally substituted by one or more hydroxy groups, C₂₋₄ alkenyl orR²¹ and R²² form together a C₂₋₅ alkylene group which may optionally beinterrupted by oxygen. Depending on the nature of R⁸, the salt may existin chelated form.

Where R⁸ is substituted (C₁₋₈ alkyl)-- or (C₁₋₈ alkoxy)carbonyl it ispreferably substituted by 1 to 4 halogen atoms selected from fluorine,chlorine and bromine.

q is preferably 1 or 2.

R¹² is preferably methyl or ethyl.

Preferably R⁶ is in the 3-position and R⁷ is in the 4-position.

Combinations of this preferred substituents are especially preferred.

Preferred particular compounds are those numbered 8, 10, 27, 30, 36 and37.

The compounds of the present invention of formula I are new substanceswhich can be prepared by methods analogous to methods known in the artfor the preparation of 2-aroyl-(bicyclic-1,3-diones) and enol ethers orenol esters thereof.

More particularly, they can be obtained by, for example: reacting anenol ester of formula (II) ##STR6## wherein Ar, X, q, R¹ -R⁴ and R⁹ -R¹⁰are as defined above, with a cyanide source and a moderate base to givea compound of formula I where R⁸ is hydrogen, followed, where desired,by etherification or esterification to the corresponding enol ethers orenol esters.

The above reaction is carried out in the presence of a catalytic amountof a source of cyanide anion and/or hydrogen cyanide, together with amolar excess, with respect to the enol ester, of a moderate base. Thereaction is conveniently carried out in a solvent which is inert underthe reaction conditions, e.g. 1,2-dichloroethane, toluene, acetonitrile,methylene chloride, ethyl acetate, dimethylformamide (DMF) and methylisobutyl ketone (MIBK). In general, depending on the nature of thereactants and the cyanide source, the rearrangement may be conducted attemperatures up to about 80° C. In some cases, for instance when thereis a possible problem of excessive by-product formation, thetemperatures should be kept at about 40° C. maximum.

Preferred cyanide sources are alkali metal cyanides such as sodium andpotassium cyanide; cyanohydrins of methyl alkyl ketones having from 1-4carbon atoms in the alkyl groups, such as acetone or methyl isobutylketone cyanohydrins; cyanohydrins of benzaldehyde or of C₂ -C₅ aliphaticaldehydes such as acetaldehyde, propionaldehyde, etc., cyanohydrins;zinc cyanide; tri(lower alkyl)silyl cyanides, notablytrimethylsilylcyanide; and hydrogen cyanide itself. Among cyanohydrinsthe preferred cyanide source is acetone cyanohydrin. The cyanide sourceis used in an amount up to about 50 mole percent based on the enolester. Generally about 1-10 mole % of the cyanide source is preferred.

By the term "moderate base" is meant a substance which acts as a baseyet whose strength or activity as a base lies between that of strongbases such as hydroxides (which could cause hydrolysis of the enolester) and that of weak bases such as bicarbonates (which would notfunction effectively). Moderate bases suitable for use in this reactioninclude both organic bases such as tertiary amines and inorganic basessuch as alkali metal carbonates and phosphates. Suitable tertiary aminesinclude trialkylamines such as triethylamine, trialkanolamines such astriethanolamine, and pyridine. Suitable inorganic bases includepotassium carbonate and trisodium phosphate. The base is used in anamount of from about 1 to about 4 moles per mole of enol ester,preferably about 1.3-2 moles per mole.

When the cyanide source is an alkali metal cyanide, particularlypotassium cyanide, a phase transfer catalyst may be included in thereaction. Particularly suitable phase transfer catalysts are the Crownethers.

Depending on the reaction conditions, the thus obtained keto-enolcompounds may be in free acid form (R⁸ is H) or in salt form; where theyare in salt form (i.e. R⁸ is a salt forming moiety), R⁸ may be inorganic(e.g. a metal equivalent of Na, Ca, Fe or Cu) or organic, e.g. theammonium salt moiety of an amine, sulfonium, sulfoxmium or phosphoniummoiety. Depending on the nature of R⁸, the salt may exist in chelatedform. The salt form may be converted to the corresponding acid form (R⁸is H) in a manner known per se, and vice versa.

Compounds of formula I where R⁸ is other than hydrogen or a salt formingmoiety can be prepared in a manner known per se for the preparation ofenol ethers or enol esters from the corresponding enol compounds, e.g.by reacting a compound of formula I where R⁸ -H with either

a) the group R⁸ -OH and a catalyst, or

b) the group R⁸ -Q and a moderate base, wherein Q is a halogen atom, togive a compound of formula I where R⁸ is as defined above other thanhydrogen or a salt forming moiety.

The above reaction a) is carried out in the presence of a catalyst suchas concentrated sulfuric acid. The reaction is conveniently carried outin a solvent which is also the reactant such as methanol, and at anelevated temperature.

The above reaction b) is carried out in the presence of a moderate basesuch as triethylamine or pyridine and conveniently at RT or below.

The compounds of formula I may be recovered from the reaction mixture inwhich they are formed by working up by established procedures.

The starting materials and reagents employed in the process describedherein are either known or, insofar as they are not known, maybeproduced in a manner analogous to the processes described herein or toknown processes.

The novel compounds of formula I are useful for the control of weeds,using pre- and/or post-emergent treatments. Compounds of formula I arealso useful as plant growth regulators and as acaricides. The compoundscan be applied for example in the form of dusts, granules, solutions,emulsions, wettable powders, flowables and suspensions. Application of acompound of the present invention as a herbicide is made according toconventional procedure to the weeds or their locus using one-half orless to ten pounds or especially one-tenth or less (e.g. one-fiftieth)to ten pounds per acre (ca 0.56 to 11.2 especially 0.112 to 11.2 kg/ha).Application as a selective herbicide in rice is made for example at arate of ca 5 to 1000 g preferably 10 to 500 g especially 20 to 200 g perhectare. The application of a compound of the present invention to the"locus" of the weed included application to the seeds, the plant (weed)or parts of the plant or the soil.

The term "herbicide," as used herein, refers to an active ingredientwhich modifies the growth of plants because of phytotoxic or plantgrowth regulating properties so as to retard the growth of the plant ordamage the plant sufficiently to kill it.

The compounds of the present invention, when applied as either post orpre-emergents, demonstrate high levels of herbicidal activity onbroadleaf, grass and sedge weeds.

Thus the compounds are useful in combatting weeds in corn (e.g.especially compound 30 hereinafter) and wheat without damaging cropcultures. Both grassy and broadleaf weeds are controlled with control ofthe latter being particularly good.

Compounds of the invention exhibit selectivity in various crops.Additionally certain compounds of formula I such as those wherein R⁸ ishydrogen or especially has the meanings given above under e) and f) oris an ammonium salt derived from an amine of formula X as defined aboveexhibit acceptable rice tolerance with excellent weed control and arethus useful for combatting weeds in rice especially in transplanted(paddy) rice.

Compounds of this type wherein X is CH₂ and each of R¹, R², R³, R⁴, R⁹and R¹⁰ is hydrogen and Ar is o-nitro-p-(O_(n) S(O)_(n), R¹²)-phenyl areespecially preferred for this use (e.g. especially compounds 8, 36 and37 hereinafter). Examples of weeds which may be selectively combatted byboth pre- and post-emergent application in rice include Echinochloa sppe.g. barnyard grass, Cyperus spp e.g. flatsedge, bullrush, spikerush,water nutsedge, Rumex spp, Sagitaria spp e.g. arrowhead, Monochoria sppand Serbania spp. They have an excellent herbicidal activity on weedsprior to germination and during growth and are useful as herbicides forsoil treatments before and after transplantation of young rice plants,during the growth of crops and for culm and foliage treatments beforetransplantation and during the growth of crops. The invention alsoprovides herbicidal commpositions suitable for use in rice locus.

In the use of the compounds of formula I as a herbicide or acaricide, acompound of formula I, or mixtures thereof, can conveniently be employedas agricultural compositions in association with acceptable diluent(s)for application to the weed, aracri, or their loci. Such compositionsalso form part of the present invention.

Methods of preparing suitable compositions which can be used with acompound of the present invention are described in the literature alongwith suitable liquid and solid carriers, such as in U.S. Pat. Nos.4,192,669 and 4,163,661, which are incorporated herein by reference. Theoptimum usage of a compound of the present invention will depend onvarious factors such as weed to be treated, incidence and/or growth ofweeds, weather, environmental conditions, formulation, applicationmethod, locus, timing and the like and is readily determinable by one ofordinary skill in the art using routine testing such as greenhousetesting and small plot testing.

The compounds of the present invention can be compounded withappropriate inert carriers, if necessary, and additivies in anappropriate ratio by means of dissolving, separating, suspending,mixing, impregnating, adsorbing or precipitating operation to formulateinto dusts, suspensions, suspension concentrates, emulsions, solutions,wettable powders, flowables, granules or tablets.

A wide variety of solids and liquids can be used as the inert diluentsor carriers in the present invention. Examples of materials which can beused as the solid carriers include vegetable powders such as soybeanmeal, corn meal, wood meal, bark meal, sawdust, tobacco stem meal,walnut shell flour, bamboo meal, fibrous meal and residue after theextraction of vegetable extract; synthetic polymers such as crushedsynthetic resins; inorganic mineral powders such as clay (e.g., kaolin,bentonite, terra abla), talc (e.g. talc, pyrophylite), silica (e.g.diatomaceous earth, siliceous sand, mica, white carbon syntheticcolloidal silica called hydrated fine silicon powder, hydrated silicicacid, or a product mainly composed of calcium silicate!, activatedcarbon, sulfur powder, pumice stone, calcined diatomaceous earth,crushed brick, fly ash, sand, calcium carbonate and calcium phosphate;and chemical fertilizers such as ammonium sulfate, ammonium phosphateand ammonium nitrate and compost. These diluents or carriers may be usedeither alone or in a combination of two or more of them. As the liquidcarriers, there can be used materials which themselves have an abilityas solvent as well as materials which themselves do not have an abilityas solvent, but can disperse active ingredients by the aid of otheradditives. Examples of the materials which can be used as the liquidcarriers include water, alcohols (e.g., methanol, ethanol, isopropanol,butanol, ethylene glycol), ketones (e.g., acetone, methyl ethyl ketone,methyl sobutyl ketone, diisobutyl ketone, cyclohexanone), ethers (e.g.,ethyl ether, dioxane, cellosolve, dipropyl ether, tetrahydrofuran),aliphatic hydrocarbons (e.g., gasoline, diesel oil, mineral oil),aromatic hydrocarbons (e.g., benzene, toluene, xylene, solvent naphtha,alkylnaphthalenes), halogenated hydrocarbons (e.g., dichloroethane,chlorinated benzene, chloroform, carbon tetrachloride), esters (e.g.,ethyl acetate, dibutyl phthalate, diisopropyl phthalate, dioctylphthalate), acid amides (e.g., dimethylformamide, diethylformamide,dimethylaceamide), nitriles (e.g., acetonitrile) and dimethyl sulfoxide.These liquid carriers maybe used either alone or as a mixture of two ormore of them.

In some cases, other additives are used either alone or as a mixture oftwo or more. In some cases, no additive is used. Surfactants are usedfor the purposes of emulsifying, dispersing, spreading, solubilizingand/or wetting the compounds as active ingredients. Examples of thesurfactants include polyoxyethylene alkylaryl ethers, polyoxyethylenealkyl ethers, polyoxyethylene higher fatty acid esters, lauryl sulfate,polyoxyethylene resin acid esters, polyoxyethylene sorbitan monolaurate,polyoxyethylene sorbitan moooleate, alkylarylsulfonates,naphthalenesulfonic acid condensate, lignosulfonates and higher alcoholsulfuric esters. For the purposes of dispersion-stabilizing, tackifyingand bonding the compound of the active ingredients, there can be used,for example, casein, gelatin, starch, alginic acid, methyl cellulose,carboxymethyl cellulose, gum arabic, polyvinyl alcohol, pine oil, tungoil, bentonite and lignosulfonates.

For the purpose of improving the fluidity of solid products, there maybe used wax, stearates and alkyl phosphates.

Naphthalenesulfonate condensates and condensed phosphates may be used aspeptizers for suspension products.

If desired, anti-foaming agents such as silicone oil, anti-caking agentsor anti-corrosion agents may be added.

Alternatively, the compounds of formula I may be used inmicro-encapsulated form.

The compounds of formula I can be combined with a cyclodextrin to make acyclodextrin inclusion complex for application to the pest or weed orits locus.

Suitable formulations contain from 0.01 to 99% by weight of activeingredient, from 0 to 20% of surfactant and from 1 to 99.99% of solid orliquid diluent(s). Higher ratios of surfactant to active ingredient aresometimes desirable and are achieved by incorporation into theformulation or by tank mixing. Application forms of a compositiongenerally contain between 0.01 and 25% by weight of active ingredient.For example powders or granules may in general contains 0.2 to 20% byweight of active ingredient. Emulsions or wettable formulations willgenerally contain 0.1 to 50% by weight of active ingredients. Lower orhigher levels of active ingredient can, of course, be present dependingon the intended use, the physical properties of the compound and themode of application. Concentrate forms of a composition intended to bediluted before use generally contain between 2 and 90%, preferablybetween 5 and 81% by weight of active ingredient.

EXAMPLE A Preparation of a Dust

10 Parts of a compound according to this invention and 90 parts ofpowdered talc are mixed in a mechanical grinder-blender and are gounduntil a homogeneous, free-flowing dust of the desired particle size isobtained. This dust is suitable for direct application to the site ofthe weed, acari infestation.

EXAMPLE B Preparation of a Wettable Powder

25 Parts of a compound according to this invention are mixed and milledwith 25 parts of synthetic fine silica, 2 parts of sodium laurylsulphate, 3 parts of sodium ligninsulphonate and 45 parts of finelydivided kaolin until the mean particle size is about 5 micron. Theresulting wettable powder is diluted with water before use to a sprayliquor with the desired concentration.

EXAMPLE C Preparation of Emulsifiable Concentrate (EC)

13.37 Parts of a compound according to this invention are mixed in abeaker with 7.04 parts of Toximul 360A (a mixture of anionic andnon-ionic surfactants containing largely anionic surfactants), 23.79parts of dimethylformamide and 55.8 parts of Tenneco 500-100(predominantly a mixture of alkylated aromatics such as xylene andethylbenzene) until solution is effected. The resulting EC is dilutedwith water for use.

EXAMPLE D Wettable Powder

50 parts of the compound No. 36, 20 parts of diatomaceous earth, 22parts of clay, 3 parts of white carbon, 2 parts of sodium lignosulfonateand 3 parts of sodium alkylnaphthalenesulfonate were mixed and crushedto obtain a wettable powder containing 50% of the active ingredient.

EXAMPLE E Granule

0.35 parts oft he compound No. 37, 25 parts of bentonite, 70.65 parts oftalc, 2 parts of sodium dodecylbenzenesulfonate and 2 parts of sodiumlignosulfonate were mixed. About 20 parts of water was added thereto.The mixture was headed in a kneader, granulated in a granulator anddried. Dressing of grain was conducted to obtain a granule containing0.35% of the active ingredient.

The compositions of this invention can also comprise other compoundshaving biological activity, e.g. compounds having similar orcomplementary herbicidal activity for broadspectrum weed control orcompounds having acaricidal activity or compounds having antidotal,fungicidal, insecticidal or insect attractant activity.

The following examples are provided to illustrate the practice of thepresent invention. Temperature is given in degrees Centigrade. RT meansroom temperature. Parts and percentages are by weight.

PREPARATION OF FINAL COMPOUNDS EXAMPLE 1

To a solution of 4-(4-chloro-2-nitrobenzoyloxy) -bicyclo-3,2,1!-3-octen-2-one (0.75 g) in 12 ml of acetonitrile are addedtriethylamine (0.62 ml) and acetone cyanohydrin (0.15 ml) in oneportion. The mixture is stirred at RT overnight, after which theacetonitrile is removed and the residue is taken up in methylenechloride, then washed with dil. HCl and with brine, dried and evaporatedto dryness. The crude product is purified by PTLC to give3-(4-chloro-2-nitrobenzoyl)-bicyclo- 3,2,1!octane-2,4-dione (compound 1,Table A).

EXAMPLE 2

To a solution of 4-(4-chloro-2-nitrobenzoyloxy)-5,8,8-trimethyl-bicyclo3,2,1!-3-octen-2-one (4.20 g) in 25 ml of acetonitrile are addedtriethylamine (3.2 ml, 2 eq.) and acetone cyanohydrin (0.4 ml), and themixture is stirred at RT for 16 hr. The acetonitrile is removed, and theresidue is concentrated and purified by PTLC to give3-(4-chloro-2-nitrobenzoyl)-1,8,8-trimethylbicyclo3,2,1!octane-2,4-dione (compound 12, Table A).

EXAMPLE 3

To a solution of 4-(3-methoxy-4-methylsulfonyloxy-2-nitrobenzoyloxy)-bicyclo 3,2,1!-3-octen-2-one (17.6 mmol) in 50 ml ofacetonitrile are added triethylamine (4.91 ml, 2 eq.) and acetonecyanohydrin (1.0 ml) in one portion. The mixture is stirred at RTovernight, after which it is diluted with water and extracted withether. The ether is removed and the residue is purified by PTLC to give3-(3-methoxy-4-methylsulfonyloxy-2-nitrobenzoyl)-bicyclo3,2,1!octane-2,4-dione (compound 9, Table A).

EXAMPLE 4

To a solution of 4-(4-methylsulfonyloxy-2-chlorobenzoyloxy)bicyclo-3,2,1!-3-octen-2-one (14.3 mmol) in 25 ml of acetonitrile are addedtriethylamine (3.97 ml, 2 eq.) and acetone cyanohydrin (0.4 ml), and themixture is stirred at RT overnight. The acetonitrile is removed, and theresidue is taken up in water and extracted with methylene chloride. Thecombined organic extracts are washed with dilute HCl and with brine,dried and evaporated to dryness. The crude product is purified fromether to give 3-(4-methylsulfonyloxy-2-chlorobenzoyl)bicyclo3,2,1!octane-2,4-dione (compound 4, Table A).

EXAMPLE 5

To a solution of 4-(3,4-methylenedioxy-2-nitrobenzoyloxy)bicyclo-3,2,1!-3-octen-2-one (13.2 mmol) in 50 ml of acetonitrile are addedtriethylamine (3.69 ml) and acetone cyanohydrin (0.5 ml) in one portion.The mixture is stirred at RT for 2 days, after which it is diluted withwater and extracted with ether. The ether is removed and the residue ispurified by PTLC to give 3-(3,4-methylenedioxy-2-nitrobenzoyl)bicyclo-3,2,1!octane-2,4-dione (compound 11, Table A).

EXAMPLE 6

To a solution of 4-(4,5-methylenedioxy-2-nitrobenzoyloxy)bicyclo-3,2,1!-3-octen-2-one (14.4 mmol) in acetonitrile are added triethylamine(4.0 ml, 28.8 mmol) and acetone cyanohydrin (0.4 ml), and the mixture isstirred at RT overnight. The acetonitrile is removed, and the residue istaken up in water and extracted with methylene chloride. The combinedorganic extracts are washed with dilute HCl and with brine, dried andevaporated to dryness. The crude product is purified by chromatographyto give 3-(4,5-methylenedioxy-2-nitrobenzoyl)-bicyclo3,2,1!octane-2,4-dione.

EXAMPLE 7

Following the procedure of any of Examples 1 through 6, each of thecompounds under Table A is prepared by rearrangement of thecorresponding enol ester.

EXAMPLE 8

A solution of 3-(4-chloro-2-nitrobenzoyl)-bicyclo3,2,1!-octane-2,4-dione (2.54 mmol) and 2 drops of conc. sulfuric acidin 20 ml of methanol is heated under reflux for 48 hours. The reactionmixture is concentrated and the residue is taken up in ether. Theethereal solution is washed with aqueous sodium bicarbonate and withbrine, dried and evaporated to dryness to give 2-methoxy-3-(4-chloro-2-nitrobenzoyl)bicyclo- 3,2,1!-octane-4-one.

EXAMPLE 9

To a mixture of 3-(4-chloro-2-nitrobenzoyl)-bicyclo -3,2,1!-octane-2,4-dione (2.26 mmol) in methylene chloride (10 ml)containing triethylamine (0.47 ml, 3.39 mmol) is added dropwise at 0° asolution of acetyl chloride (0.27 g, 3.39 mmol) in 5 ml of methylenechloride. The resulting mixture is stirred for 30 min., and is thendiluted with methylene chloride, washed, dried and evaporated to drynessto give 4-acetoxy-3-(4-chloro-2-nitrobenzoyl)-bicyclo3,2,1!-3-octen-2-one.

EXAMPLE 10

Following the procedure of Example 9, the final compounds under column Iare prepared by the reaction of 3-(4-chloro-2-nitrobenzoyl)-bicyclo3,2,1!octane-2,4-dione with the corresponding acyl chloride.

I

31. 4-propionyloxy-3-(4-chloro-2-nitrobenzoyl)-bicyclo-3,2,1!-3-octen-2-one

32. 2-isobutyryloxy-3-(4-chloro-2-nitrobenzoyl)-bicyclo-3,2,1!-3-octen-2-one

33. 2-pivaloyloxy-3-(4-chloro-2-nitrobenzoyl)-bicyclo-3,2,1!-3-octen-2-one

34. 2-benzoyloxy-3-(4-chloro-2-nitrobenzoyl)-bicyclo-3,2,1!-3-octen-2-one

35. 4-pivaloyloxy-3-(4-chloro-2-nitrobenzoyl)-bicyclo-3,2,1!-3-octen-2-one (foam)

EXAMPLE 11 Preparation of4-benzoyloxy-3-(4-methylsulfonyl-2-nitrobenzoyl)-bicyclo-3,2,1!-3-octen-2-one (compound no. 36)

To a solution of 2.0 g of 3-(4-methylsulfonyl-2-nitrobenzoyl)-bicyclo-3,2,1!-octane-2,4-dione and 0.8 g of triethylamine in 30 ml of methylenedichloride is added 0.77 g of benzoyl chloride in 5 ml of methylenedichloride at 0° and the mixture stirred for one hour at 0°. Theresulting solution is diluted with methylene dichloride, washed withbrine, dried and evaporated to dryness. The crude product is purified bysilica gel column chromatography to give the solid which is washed withisopropyether m.p. 142°-144°.

EXAMPLE 12 Preparation of the triethylammonium salt of4-hydroxy-3-(4-methylsulfonyl-2-nitrobenzoyl)-bicyclo-3,2,1!-3-octen-2-one (compound no. 37)

0.8 g of 3-(4-methylsulfonyl-2-nitrobenzoyl) -bicyclo-3,2,1!-octane-2,4-dione and 0.5 ml of triethylamine are stirred in 20 mlof methylene dichloride at RT for one hour. Evaporation of the solutionand recrystalization from isopropylether gave the title compound m.p.126°-7°.

                                      TABLE A                                     __________________________________________________________________________     ##STR7##                                                                                                       m.p.                                        Cpd X    q  R.sup.9                                                                           R.sup.10                                                                          R.sup.5                                                                           R.sup.6                                                                            R.sup.7                                                                            (°C.)                                __________________________________________________________________________    1   CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          H    Cl   134                                         2   CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          H    Br   142                                         3   CH.sub.2                                                                           1  H   H   Cl  H    SO.sub.2 CH.sub.3                                                                  foam                                        4   CH.sub.2                                                                           1  H   H   Cl  H    OSO.sub.2 CH.sub.3                               5   CH.sub.2                                                                           1  H   H   Cl  Cl   Cl                                               6   CH.sub.2                                                                           1  H   H   Cl  Cl   SO.sub.2 CH.sub.3                                7   CH.sub.2                                                                           1  H   H   CH.sub.3                                                                          H    Br   92-95                                       8   CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          H    SO.sub.2 CH.sub.3                                                                  148                                         9   CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          OCH.sub.3                                                                          OSO.sub.2 CH.sub.3                               10  CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          H    OSO.sub.2 CH.sub.3                                                                 140                                         11  CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          OCH.sub.2O                                            12  C(CH.sub.3).sub.2                                                                  1  H   CH.sub.3                                                                          NO.sub.2                                                                          H    Cl   101                                         13  O    1  CH.sub.3                                                                          CH.sub.3                                                                          NO.sub.2                                                                          H    Cl   foam                                        14  O    1  CH.sub.3                                                                          CH.sub.3                                                                          NO.sub.2                                                                          H    Br                                               15  O    1  CH.sub.3                                                                          CH.sub.3                                                                          CH.sub.3                                                                          H    Br                                               16  O    1  CH.sub.3                                                                          CH.sub.3                                                                          Cl  Cl   Cl                                               17  O    1  CH.sub.3                                                                          CH.sub.3                                                                          Cl  Cl   SO.sub.2 CH.sub.3                                18  O    1  CH.sub.3                                                                          CH.sub.3                                                                          Cl  H    SO.sub.2 CH.sub.3                                19  O    1  CH.sub.3                                                                          CH.sub.3                                                                          NO.sub.2                                                                          H    SO.sub.2 CH.sub.3                                20  O    1  CH.sub.3                                                                          CH.sub.3                                                                          NO.sub.2                                                                          OCH.sub.3                                                                          OSO.sub.2 CH.sub.3                               21  O    1  CH.sub.3                                                                          CH.sub.3                                                                          Cl  H    OSO.sub.2 CH.sub.3                               22  O    1  CH.sub.3                                                                          CH.sub.3                                                                          NO.sub.2                                                                          H    OSO.sub.2 CH.sub.3                               23  CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          H    SCH.sub.2 CH.sub.3                                                                  75                                         24  CH.sub.2                                                                           1  H   H   CH.sub.3                                                                          H    Cl    94                                         25  CH.sub.2                                                                           2  H   H   NO.sub.2                                                                          H    Cl   138                                         26  CH.sub.2                                                                           2  H   H   NO.sub.2                                                                          H    F     96                                         27  CH.sub.2                                                                           2  H   H   NO.sub.2                                                                          H    OSO.sub.2 CH.sub.3                                                                 167                                         28  CH.sub.2                                                                           2  H   H   NO.sub.2                                                                          H    SO.sub.2 CH.sub.3                                                                  160                                         29  CH.sub.2                                                                           2  H   H   NO.sub.2                                                                          H    SCH.sub.3                                                                          145-147                                     30  CH.sub.2                                                                           1  H   H   NO.sub.2                                                                          H    SCH.sub.3                                                                          126                                         __________________________________________________________________________

The starting compounds of formula II herein are known or, in cases wherethey are not, can be produced by methods analogous to known methods orby methods described herein.

Thus, the enol esters of formula II can be prepared by the reaction of a3,5-dione of formula III with a benzoyl halide of formula IV (wherein Qis a halogen atom) in the presence of a moderate base such astriethylamine. ##STR8##

The bicycloalkane diones of formula III can be synthesized by themethods such as a) described by Hiroshi Kakisawa et al., Bull. Chem.Soc. Jpn., 60:4369 (1987), or b) by oxidizing the knownhydroxy-oxabicyclo 2,2,1!heptane (U.S. Pat. No. 4,670,041 ) tooxabicyclo 2,2,1!heptane-2,3-diones. Ring expansion of oxabicyclo2,2,1!heptane-2,3-dione with alkyl diazoacetate (described byKorobitsyna et al., J. Gen. Cheml USSR 27:1859 (1957)) followed byheating in the presence of water, may also be used.

INTERMEDIATE COMPOUNDS

The following examples are presented to illustrate representativemethods of preparing the intermediate compounds.

EXAMPLE 13

4-Chloro-2-nitrobenzoic acid (0.430 g, 2.13 mmol) is heated under refluxwith thionyl chloride for 2 hr., after which excess thionyl chloride isremoved under vacuum. The resulting acid chloride residue in 5 ml ofmethylene chloride is added to bicyclo 3,2,1!octane-2,4-dione (0.294 g,2.13 mmol) dissolved in 10 ml of methylene chloride, with cooling to 0°,followed by dropwise addition of triethylamine (0.50 ml, 3.40 mmol). Themixture is stirred at RT for 30 min. and is then taken up in methylenechloride. The organic layer is washed with brine, dried and evaporatedto give 4-(4-chloro-2-nitrobenzoyloxy)-bicyclo 3,2,1!-3-octen-2-one.

EXAMPLE 14

To a solution of (±) camphorquinone (1,7,7) -trimethylbicyclo3,2,1!-heptane-2,3-dione! (15.0 g, 90.24 mmol) and ethyl diazoacetate(11.8 g, 103.7 mmol) in 120 ml of ether is added, at 0°, BF₃.ether (4ml). The mixture is stirred at RT for 24 hr. The reaction mixture isextracted with 5% K₂ CO₃ /H₂ O until no polar ethyl carboxyl dioneremains. The combined aqueous extracts are acidified with conc. HCl andextracted with ether. The combined organic extracts are dried andevaporated to dryness to give crystalline3-carboethoxy-1,8,8-trimethylbicyclo 3,2,1 !octane-2,4-dione.

The above octane-2,4-dione (5.0 g, 19.8 mmol) in 20 ml ofdimethylsulfoxide (DMSO) and 0.8 ml of water is heated at 130°-140° for1 hr. The reaction mixture is diluted with ether, washed with water andwith brine, dried and evaporated to give crystalline1,8,8-trimethylbicyclo 3,2,1!-octane-2,4-dione, m.p. 220°.

EXAMPLE 15

To a solution of 1,8,8-trimethylbicyclo 3,2,1!octane-2,4-dione (2.0 g,11.0 mmol) in 25 ml of methylene chloride containing triethylamine (2.30ml, 16.0 mmol) is added, dropwise at 0°, a solution of4-chloro-2-nitrobenzoyl chloride, prepared from the corresponding acid(2.23 g, 11.0 mmol) and thionyl chloride, in methylene chloride (5 ml).After the addition is complete, the mixture is warmed to RT and stirredfor 1 hr. at RT, after which it is diluted with methylene chloride,washed, dried and evaporated to dryness to give a mixture of4-(4-chloro-2-nitrobenzoyloxy)-5,8,8-trimethylbicyclo3,2,1!-3-octen-2-one and 4-(4-chloro-2-nitrobenzoyloxy)-1,8,8-trimethylbicyclo 3,2,1!-3-octen-2-one.

EXAMPLE 16

To a solution of 4-hydroxy-3-methoxy-2-nitrobenzaldehyde (10.0 g, 50.7mmol) in 200 ml of methylene chloride and containing triethylamine(10.60 ml, 1.5 eq.) at 0° is added methanesulfonyl chloride (4.32 ml,6.39 g, 1.1 eq.) over a period of 5-10 min. The mixture is stirred foran additional 10 min., and is then washed with ice water, with diluteHCl, with sat. NaHCO₃ and with brine. The layers are separated and theorganic layer is dried and evaporated to give3-methoxy-4-methylsulfonyoxy-4-nitrobenzaldehyde.

The above aldehyde (13.25 g) is suspended in acetone and cooled to 0°.Jones reagent is added dropwise over approx. 15 min. until the solutionis slightly orange, indicating an excess of the reagent. The reaction isstirred for approx. 1 hr., after which it is diluted with water andextracted with ethylacetate to give3-methoxy-4-methylsulfonyloxy-2-nitrobenzoic acid.

EXAMPLE 17

3-Methoxy-4-methylsulfonyloxy-2-nitrobenzoic acid (5.13 g, 17.6 mmol) isheated under reflux with thionyl chloride for 2 hr., after which excessthionyl chloride is removed under vacuum. The resulting acid chlorideresidue is added to bicyclo 3,2,1!octane-2,4-dione (17.6 mmol) dissolvedin 50 ml of methylene chloride, with cooling to 5°, followed by dropwiseaddition of triethylamine (3.19 ml, 1.3 eq.). The mixture is stirred atRT for 2 hr. and then poured into water. The organic layer is washedwith brine, dried and evaporated to give4-(3-methoxy-4-methylsulfonyloxy-2-nitrobenzoyloxy)bicyclo3,2,1!-3-octen-2-one.

EXAMPLE 18

To a solution of 2-chloro-4-hydroxybenzoic acid (3.45 g, 20 mmol) andsodium hydroxide (2.40 g, 60.0 mmol) in 30 ml of water is added,dropwise at 0°, methanesulfonyl chloride (2.57 ml, 3.80 g, 33.0 mmol).After addition is complete, the reaction mixture is stirred at RT for 30min., after which it is poured into water, acidified with dil. HCl andextracted with ether. The combined organic extracts are washed withbrine, dried and evaporated to give 2-chloro-4-methylsulfonyloxybenzoicacid.

EXAMPLE 19

To a solution of bicyclo 3,2,1!octane-2,4-dione (14.0 mmol) in 20 ml ofmethylene chloride containing triethylamine (2.90 ml, 20.8 mmol) isadded, dropwise at 0°, a solution of 2-chloro-4-methylsulfonyloxybenzoylchloride, prepared from the corresponding acid (3.50 g, 14.0 mmol) andthionyl chloride, in methylene chloride (10 ml). After the addition iscomplete, the mixture is stirred for another 30 min. at 0°, after whichit is diluted with methylene chloride, washed, dried and evaporated todryness to give 4-(2-chloro-4-methylsulfonyloxybenzoyloxy) -bicyclo3,2,1!-3-octen-2-one.

EXAMPLE 20

Silver oxide is prepared by adding a solution of silver nitrate (43.53g, 0.26 mol) in 100 ml of water to a solution of sodium hydroxide (20.48g, 0.51 mol) in 100 ml of water. To this brown semisolid mixture isadded 6-nitropiperonal (25.0 g, 0.128 mol) in small portions withvigorous stirring. The reaction mixture is stirred for 2 hr. at 50°. Themixture is then filtered, and the filtrate is acidified, and extractedwith ether. The ether extracts are dried and the ether evaporated off togive, after trituration with ether/hexane,6-nitro-1,3-benzodioxole-5-carboxylic acid.

EXAMPLE 21

6-Nitro-1,3-benzodioxole-5-carboxylic acid (2.71 g) is heated underreflux with 25 ml of thionyl chloride for 2 hr., after which excessthionyl chloride is removed under vacuum. The resulting acid chlorideresidue is added to bicyclo 3,2,1!-octane-2,4-dione (11.8 mmol)dissolved in methylene chloride, with cooling to 5°, followed bydropwise addition of triethylamine (1.3 eq.). The mixture is stirred atRT for 2 hr. and then poured into water. The organic layer is washedwith brine, dried and evaporated to give4-(4,5-methylenedioxy-2-nitrobenzoyloxy) bicyclo- 3,2,1!-3-octen-2-one.

BIOASSAY EXAMPLE F

Paddy soil in plastic pots (200 cm³) was just flooded and then puddled.Water depth was maintained at 4 cm during testing without water drainagetreatment. The field was seeded with barnyard-grass, monochoria, ammaniaand bulrush. The tubers of Sagittaria trifolia, pygmaea, water nutsedgeand water chestnut were buried in the field. Six rice seedlings in adiphyllous stage (breed: Koshihikari, 1 cm plating: 3 rice seedlings, 3cm plating: 3 rice seedlings) per pot were transplanted. After 10 daysfrom the transplantation, the powder formulated according to Example Ewas spread over the surface of water. On the next day after theapplication and on the day after next, water was allowed to leak out ata rate of 3 cm/day. On the 21st day after the application, evaluationwas made by observing degree of damage to the plants.

Excellent weed control is achieved with little or no rice crop damage atrates of 125 g/ha or less using e.g. compounds 8, 36 and 37.

EXAMPLE G

a) Preemergent

Weeds and crop plants are seeded two per pot and covered with soil. Theactive ingredient is sprayed onto the surface of the soil at the chosenapplication rate with a spray volume equivalent to 600 L/Ha (50%acetone, 1/2% surfactant, remainder water). 4 pots per a.i. and species.Evaluation of percentage control takes place at 10 and 28 days postapplication.

b) Postemergent

Methodology as a) except that spraying takes place at the 2 leaf stageand evaluation of percentage control after 14 and 28 days.

Excellent control of both broadleaf and grassy weeds was obtained at 300g/ha or less with low damage to corn and rice e.g. with compounds 8, 10and 27.

What is claimed is:
 1. A compound having the formula I ##STR9## wherein,Ar is selected from the groups ##STR10## X is oxygen or; each of R¹, R²,R³, R⁴, R⁹ and R¹⁰ is, independently, hydrogen, C₁₋₈ alkyl or COOR¹⁶ ;R⁵is C₁₋₈ alkyl, optionally substituted with one to six halogen atoms;C₁₋₈ alkoxy, optionally substituted with one to six halogen atoms; C₁₋₈alkylcarbonyl; C₁₋₈ alkoxycarbonyl; NR¹³ R¹⁴ ; O_(n) S(O)_(n') R¹² ;NR¹⁵ SO₂ R¹² ; halogen; cyano; or nitro; each of R⁶ and R⁷ isindependently hydrogen or selected from the values of R⁵ ; or R⁶ and R⁷together form the group -Y-W-Z-; R⁸ is hydrogen, C₁₋₈ alkyl, optionallysubstituted with one to four halogen atoms, C₁₋₈ alkylcarbonyl, C₁₋₈alkoxycarbonyl, optionally substituted with one to four halogen atoms,C(O)NR¹³ R¹⁴, C₁₋₈ alkylsulfonyl, P(O)--(OR¹¹)₂, R¹³ P(O)OR¹¹ or benzoylor a salt forming moiety; R¹¹ is C₁₋₈ alkyl; R¹² is C₁₋₈ alkyl,optionally substituted with one to six halogen atoms; each of R¹³, R¹⁴,R¹⁵ and R¹⁶ is, independently, hydrogen or C₁₋₈ alkyl; each of R¹⁷ andR¹⁸ is independently hydrogen, halogen, or C₁₋₈ alkyl optionallysubstituted with one to six halogen atoms; or R¹⁷ and R¹⁸ together forman oxo group; each of R¹⁹ and R²⁰ is, independently, hydrogen, halogen,or C₁₋₈ alkyl optionally substituted with one to six halogen atoms; W is--(CR¹⁷ R¹⁸)_(t) --(CR¹⁹ R²⁰)_(t) -- or SO₂ ; each of Y and Z isindependently oxygen, sulfur, SO₂, C═O or CR¹⁵ R¹⁶ ; with the provisothat Y and Z are attached to adjacent carbons; n is zero or one; n' iszero, one or two; q is zero, one or two; t is one or two; and t' is zeroor one.
 2. A compound according to claim 1 wherein R⁸ is hydrogen, C₁₋₈alkyl, C₁₋₈ alkylcarbonyl, C₁₋₈ alkoxycarbonyl, C(O)NR¹³ R¹⁴, C₁₋₈alkylsulfonyl, P(O)--(OR¹¹)₂, R¹³ P(O)OR¹¹ or benzoyl.
 3. A compoundaccording to claim 1 wherein R⁸ is optionally substituted C₁₋₈alkylcarbonyl, optionally substituted C₁₋₈ alkoxycarbonyl or optionallysubstituted benzoyl or is an ammonium salt derived from an amine offormula X ##STR11## wherein each of R²¹, R²² and R²³ representsindependently hydrogen, C₁₋₁₆ alkyl optionally substituted by one ormore hydroxy groups, C₂₋₄ alkenyl or R²¹ and R²² form together a C₂₋₅alkylene group which may optionally be interrupted by oxygen.
 4. Acompound according to claim 1 wherein Ar is the group ##STR12##
 5. Acompound according to claim 4 wherein X is oxygen q is one, and each ofR¹, R², R³, R⁴, R⁹ and R¹⁰ is independently hydrogen or C₁₋₄ alkyl.
 6. Acompound according to claim 5 wherein R⁵ is C₁₋₄ alkyl optionallysubstituted with one to three halogen atoms, --(O)_(n) --S(O)_(n') C₁₋₄alkyl, halogen, or nitro.
 7. A compound according to claim 6 wherein R⁵is methyl, CF₃, bromo, chloro, nitro or OSO₂ CH₃ and R⁸ is hydrogen,C₁₋₄ alkyl, C₄₋₈ alkylcarbonyl or benzoyl.
 8. A compound according toclaim 7 wherein R⁶ is in the 3-position and is hydrogen, methoxy, chloroor OSO₂ CH₃, and R⁷ is in the 4-position and is methoxy, CF₃, bromo,chloro, nitro, OSO₂ R¹² or NHSO₂ R¹² where R¹² is methyl, CH₂ Cl or CF₃.9. A compound according to claim 8 wherein R⁵ is nitro and R⁶ ishydrogen.
 10. A compound according to claim 1 wherein X is oxygen andeach of R¹, R², R³, R⁴, R⁹, and R¹⁰ is independently hydrogen, methyl orethyl.
 11. A compound according to claim 4 wherein, q is 1 or 2, R⁹ andR¹⁰ are hydrogen, R⁵ is nitro or chloro, R⁶ is hydrogen and R⁷ isfluoro, chloro, bromo, S-C₁₋₄ alkyl, SO₂ -C₁₋₄ alkyl, OSO₂ -C₁₋₄ alkyl.12. A compound according to claim 11 wherein R⁸ is hydrogen.
 13. Acompound according to claim 4 selected from those wherein R¹, R², R³,R⁴, R⁶, R⁹ and R¹⁰ are hydrogen, R⁵ is nitro anda) q is 1 and R⁷ isp-SCH₃ ; or b) q is 1 and R⁷ is p-SO₂ CH₃ ; or c) q is 1 and R⁷ isp-OSO₂ CH₃ ; or d) q is 2 and R⁷ os p-OSO₂ CH₃.
 14. A compound accordingto claim 13 wherein R⁸ is hydrogen.
 15. A compound according to claim 13wherein R⁸ is as defined in claim
 4. 16. An agricultural compositioncomprising an effective amount of a compound according to claim 1together with an agriculturally acceptable carrier.
 17. A method for thecontrol of weeds which comprises applying to the weed or its locus anherbicidally effective amount of a compound of formula I according toclaim
 1. 18. A method for selectively controlling weeds in rice whichcomprises applying to the weeds or their locus a herbicidally effectiveamount of a compound of formula I according to claim
 1. 19. A compoundaccording to claim 4 wherein X is O; R¹, R², R³ and R⁴ are hydrogen; R⁵is methyl, CF₃, C₁₋₃ alkylsulfonyl, C₁₋₃ alkylsulfonoxy, chloro, bromoor nitro; R⁶ is hydrogen or together with R⁷ methylenedioxy; R⁷ ischloro, fluoro, bromo, C₁₋₄ alkylthio, C₁₋₃ alkylsulfonyl or C₁₋₃alkylsulfonyloxy, or together with R⁶ methylenedioxy; R⁹ and R¹⁰ areindependently hydrogen or C₁₋₃ alkyl; and q is one or two.
 20. Acompound according to claim 19 wherein R⁸ is other than hydrogen or asalt forming moiety.
 21. An agricultural composition comprising aneffective amount of a compound according to claim 2 together with anagriculturally acceptable carrier.
 22. An agricultural compositioncomprising an effective mount of a compound according to claim 4together with an agriculturally acceptable carrier.
 23. A method forselectively controlling weeds which comprises applying to the weed orits locus an herbicidally effective amount of a compound according toclaim 4.